Multiplexed regenerated fiber Bragg gratings for high-temperature measurement

A high-temperature gradient of a conventional tubular furnace is characterized using a single-fiber sensing line with wavelength-multiplexed short-length-regenerated fiber Bragg gratings. The multiplexed gratings are simultaneously regenerated using a high-temperature annealing process. Temperature calibration from ambient temperatures up to 900 degrees C is conducted leading to a standard deviation of 0.15 degrees C after the polynomial fitting of the wavelength shift with the temperature.